Three-dimensional (3D) sensors are used to measure loads within vehicle trailers and shipping containers. 3D sensors, for example, measure distances from a back-wall of a trailer/container to the nearest load-wall inside that trailer/container. From these distances, operators can determine such metrics as the available storage space within a volume
Current 3D sensors are structured light (SL) 3D sensors used in Trailer Monitor Units (TMUs) mounted on vehicle trailers. For SL sensors, a projector projects an image into a volume (of the trailer/container), multiple cameras capture renditions of the projected image, and these renditions are image processed to determine relative distances of the back wall and objects in the volume. The process requires complex and time-consuming image processing, and the results are often inaccurate. Specifically, SL sensors are highly dependent on the light intensity in a volume. Yet, light intensity changes dramatically with the number of objects in the volume, or when differently shaped or differently sized objects are placed in the volume. The result is that conventional 3D sensors are of limited effectiveness in “smart” shipping application, where accurate assessment of trailer loads is desired.
Accordingly, there is a need for a system of illuminating a volume with an illumination pattern that maintains sufficient irradiance within a volume for accurate measurements of objects within the volume, while maintaining a maximum irradiance that provides safe operation of personnel within the volume.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.